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Related papers: A Three-Point Cosmic Ray Anisotropy Method

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Spatially referenced data often have autocovariance functions with elliptical isolevel contours, a property known as geometric anisotropy. The anisotropy parameters include the tilt of the ellipse (orientation angle) with respect to a…

Statistics Theory · Mathematics 2021-10-04 Manolis P. Petrakis , Dionissios T. Hristopulos

This paper proposes parametric and non-parametric hypothesis testing algorithms for detecting anisotropy -- rotational variance of the covariance function in random fields. Both algorithms are based on resampling mechanisms, which enable…

Methodology · Statistics 2021-06-08 Assaf Rabinowicz , Saharon Rosset

Anisotropy in arrival directions of ultrahigh energy cosmic rays offers the most direct way to search for the sources of these particles. We present estimates of the angular correlation in the HiRes sample of stereo events above 10 EeV, and…

Astrophysics · Physics 2019-08-15 Chad Finley

The two point correlation function of the CMB temperature anisotropies is generally assumed to be statistically isotropic (SI). Deviations from this assumption could be traced to physical or observational artefacts and systematic effects.…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-11 Saurabh Kumar , Aditya Rotti , Moumita Aich , Nidhi Pant , Sanjit Mitra , Tarun Souradeep

This study presents preliminary results from the analysis of cosmic-ray anisotropy using air showers detected by the IceTop surface array between 2011 and 2022. With improved statistical precision and updated Monte Carlo simulation events…

High Energy Astrophysical Phenomena · Physics 2025-08-01 Rasha Abbasi , Paolo Desiati , Juan Carlos Díaz Vélez , Frank McNally

We employ the time-dependent R-Matrix (TDRM) method to calculate anisotropy parameters for positive and negative sidebands of selected harmonics generated by two-color two-photon above threshold ionization of argon. We consider odd…

Atomic Physics · Physics 2013-10-24 Steven Hutchinson , Michael A. Lysaght , Hugo W. van der Hart

In parallel with advances in microscale imaging techniques, the fields of biology and materials science have focused on precisely extracting particle properties based on their diffusion behavior. Although the majority of real-world…

Mesoscale and Nanoscale Physics · Physics 2024-05-22 Kaito Takanami , Daisuke Taniguchi , Sawako Enoki , Masafumi Kuroda , Yasushi Okada , Yoshiyuki Kabashima

Motivated by the detection of a significant dipole structure in the arrival directions of ultrahigh-energy cosmic rays above 8 EeV reported by the Pierre Auger Observatory (Auger), we search for a large-scale anisotropy using data collected…

High Energy Astrophysical Phenomena · Physics 2020-07-28 Telescope Array Collaboration , R. U. Abbasi , M. Abe , T. Abu-Zayyad , M. Allen , R. Azuma , E. Barcikowski , J. W. Belz , D. R. Bergman , S. A. Blake , R. Cady , B. G. Cheon , J. Chiba , M. Chikawa , A. di Matteo , T. Fujii , K. Fujisue , K. Fujita , R. Fujiwara , M. Fukushima , G. Furlich , W. Hanlon , M. Hayashi , N. Hayashida , K. Hibino , R. Higuchi , K. Honda , D. Ikeda , T. Inadomi , N. Inoue , T. Ishii , R. Ishimori , H. Ito , D. Ivanov , H. Iwakura , H. M. Jeong , S. Jeong , C. C. H. Jui , K. Kadota , F. Kakimoto , O. Kalashev , K. Kasahara , S. Kasami , H. Kawai , S. Kawakami , S. Kawana , K. Kawata , E. Kido , H. B. Kim , J. H. Kim , J. H. Kim , M. H. Kim , S. W. Kim , S. Kishigami , V. Kuzmin , M. Kuznetsov , Y. J. Kwon , K. H. Lee , B. Lubsandorzhiev , J. P. Lundquist , K. Machida , H. Matsumiya , T. Matsuyama , J. N. Matthews , R. Mayta , M. Minamino , K. Mukai , I. Myers , S. Nagataki , K. Nakai , R. Nakamura , T. Nakamura , Y. Nakamura , Y. Nakamura , T. Nonaka , H. Oda , S. Ogio , M. Ohnishi , H. Ohoka , Y. Oku , T. Okuda , Y. Omura , M. Ono , R. Onogi , A. Oshima , S. Ozawa , I. H. Park , M. S. Pshirkov , J. Remington , D. C. Rodriguez , G. Rubtsov , D. Ryu , H. Sagawa , R. Sahara , Y. Saito , N. Sakaki , T. Sako , N. Sakurai , K. Sano , T. Seki , K. Sekino , P. D. Shah , F. Shibata , T. Shibata , H. Shimodaira , B. K. Shin , H. S. Shin , J. D. Smith , P. Sokolsky , N. Sone , B. T. Stokes , T. A. Stroman , T. Suzawa , Y. Takagi , Y. Takahashi , M. Takamura , M. Takeda , R. Takeishi , A. Taketa , M. Takita , Y. Tameda , H. Tanaka , K. Tanaka , M. Tanaka , Y. Tanoue , S. B. Thomas , G. B. Thomson , P. Tinyakov , I. Tkachev , H. Tokuno , T. Tomida , S. Troitsky , Y. Tsunesada , Y. Uchihori , S. Udo , T. Uehama , F. Urban , T. Wong , K. Yada , M. Yamamoto , K. Yamazaki , J. Yang , K. Yashiro , M. Yosei , Y. Zhezher , Z. Zundel

The distribution of arrival directions of ultra-high energy cosmic rays may yield clues to their mysterious origin. We introduce a method of {\it invariant statistics} to analyze cosmic ray data which eliminates coordinate-dependent…

Astrophysics · Physics 2009-11-07 Soebur Razzaque , John P. Ralston

We propose a new method to determine the dipole (and quadrupole) component of a distribution of cosmic ray arrival directions, which can be applied when there is partial sky coverage and/or inhomogeneous exposure. In its simplest version it…

Astrophysics · Physics 2009-11-11 Silvia Mollerach , Esteban Roulet

In this study, we investigated the anisotropy of diffusive Ultra-High Energy Cosmic Rays (UHECRs) by employing three cosmological models: two models from the $f(R, T)$ gravity theory and the other is the standard $\Lambda$CDM model. The…

High Energy Astrophysical Phenomena · Physics 2025-09-03 Swaraj Pratim Sarmah , Umananda Dev Goswami

We propose a novel method for testing isotropy of a three-dimensional distribution using Shannon entropy. We test the method on some Monte Carlo simulations of isotropic and anisotropic distributions and find that the method can effectively…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-24 Biswajit Pandey

Measurements of anisotropies in the arrival directions of ultra-high-energy cosmic rays are crucial to pinpoint their sources, which are yet to be discovered. A dipolar anisotropy in right ascension above 8~EeV has been detected by the…

High Energy Astrophysical Phenomena · Physics 2025-07-28 Marta Bianciotto

Context. At large angular scales, the Pierre Auger Observatory has reported a significant dipole modulation in right ascension, while at intermediate angular scales, localized flux excesses have been identified by both the Auger and…

High Energy Astrophysical Phenomena · Physics 2026-01-13 D. Allard , J. Aublin , B. Baret , E. Parizot

The methodical properties of the original difference method for the search of the anisotropy at the knee region of the primary cosmic radiation energy spectrum are analyzed. The main feature of the suggested method is a study of the…

Instrumentation and Methods for Astrophysics · Physics 2015-10-01 V. P. Pavlyuchenko , R. M. Martirosov , N. M. Nikolskaya , A. D. Erlykin

Analyses of recent cosmic microwave background (CMB) observations have provided increasing indications for the existence of large scale anisotropy in the universe. Given the far reaching consequences of such an anisotropy for our…

Astrophysics · Physics 2009-09-29 A. Bernui , B. Mota , M. J. Reboucas , R. Tavakol

We present a novel catalog-independent method, based on a scale dependent approach, to detect anisotropy signatures in the arrival direction distribution of the ultra highest energy cosmic rays (UHECR). The method provides a good…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 M. De Domenico , H. Lyberis , A. Insolia , M. Scuderi

We present a new method to estimate three-point correlations in Cosmic Microwave Background maps. Our Fast Fourier Transform based implementation estimates three-point functions using all possible configurations (triangles) at a controlled…

Astrophysics · Physics 2009-11-13 Gang Chen , Istvan Szapudi

An anisotropy signal for the arrival directions of ultra-high energy cosmic rays (UHECR) of more than 99% confidence level was established using data collected by the Pierre Auger Observatory. Cosmic rays with energy above $\sim 6 \times…

High Energy Astrophysical Phenomena · Physics 2019-08-14 E. M. Santos

A search for anisotropy at different scales in the arrival directions of cosmic rays with energies above 1 PeV is performed with data of the Tunka-133 array. A number of regions with angular sizes up to approximately 30 degrees that deviate…

High Energy Astrophysical Phenomena · Physics 2014-02-19 M. Yu. Zotov